I picked up my SR22 today and aside from looking similar externally it is a very different design than my P22Q. The Ruger is well built and handles nicely. 200 rounds today with no hiccups. My P22 has been extremely reliable as well with over 3000 rounds fired but how it will hold up in the long run with the zinc slide is a bit of a question mark for me. I stick to standard and high velocity and try to avoid hyper velocity loads to try to keep the stress on the slide to a minimum. If someone could make an aftermarket aluminum slide for the P22 at a reasonable cost I would bet they could sell a ton of them.

For all of you who have or will purchase a SR22, apparently plenty are leaving the factory with the barrel screw loose. Job one should be to clean the pistol and make sure the barrel screw is tight. I'd install some blue threadlocker. Apparently a round pin sits in a channel under the chamber area and the pin is peening the channel when the pistol is fired with the screw not properly torqued down.

There is also an identical gouging of aluminum from the bottom of the left side where a sharp slide stop arm drags. Same fix applies as with the P22, check the top, rear edge of the slide stop and slightly round it so it won't gouge into the zinc. The hardened pin can actually peen the metal in the arm so I'd advise keeping an eye on it every 1,000 rounds or so. M1911

A person on other forum suggested that the loose barrel nut could be sabotage by an anti-gun person or competitor bribed one. That is not so far off to me. A couple of weeks after I received my MKIII, the sear pin broke. It supposed to be solid steel. But when I looked at it under a magnifier, a very small center steel pin was overlay-ed by a very fragile darker-then-steel material. But to look at it w/o something handy to compare it, a person would think it was solid steel.
The steel pin was actually 2 pieces bound together by this fragile outer layer. It was a very good design for failure. Nothing else makes sense. There was several others that had broken sear pins in ~ a 6 week period. Ruger sent me a return envelope with a another sear pin. I also got a stainless steel one, which is the one in the pistole now.

I'm doubting any antis...might be a Walther P22 lover but I doubt that too. More likely rushing those pistols down the line at ubber speed so they can make plenty of money. But, this is why I'm waiting. I've seen this before. I'm not sure that round peg in the rectangular slot is going to cut it. Certainly Ruger wouldn't have missed this.........oh I don't know, relatively few changes from MKII to MKIII and that ugly loaded round indicator was all metal on the first versions.

Let's see, rim of a cartridge in the chamber pivots the metal loaded chamber indicator out the left side of the pistol. Wonder what happens if you bang the indicator against the edge of your desk.......OOOOOOOOOOOPS ! At least Ruger got with the program pronto and fixed it. But you have to ask yourself how did Ruger make such a major screw up.

Gonna be hard to have sympathy for Walther. We've been telling them for 10 years what needs fixing. Bean counters, wonder what they will think when Ruger takes over the sale of P22 type pistols. M1911

If I knew for fact that the Ruger was reliable, I'd be tempted to buy one, seeing as how the P22 has had issues for a long time now that remain unresolved unless you personally want to become an overnight gunsmith. But keep in mind that it's a new model for Ruger, and new models often have bugs and kinks to iron out or squish. Even a solid company like Ruger is not immune ... as witnessed by the recent Kel-Tec clone that experienced a near-instant recall, IIRC.

Lower the price to that of a SR22 including two mags.
Properly re-profile the hammer face to eliminate it hanging up the slide.
Thicken the slide to eliminate it cracking, there is plenty of umph to still cycle.
Better sights/sight options.
Polish those trigger bar ears.
Include a small supply of moly powder for the frame rails.
Shorter recoil spring for easier assembly.

Then I think it could hold it's ground with the Ruger.

I'm not a metallurgist but will aluminum wear any better than a properly designed MIM'd zinc slide? M1911

6061 grade is also used for aircraft parts, is more common and less expensive then then the 7075. I have used the 6061 and have some stock of it now. I still want to mill a slide for my P22 after I get over my just acquired passion for the Ruger MK series, which could be a heck of a long time. :-)
I know I will make the prototypes ones with the 6061 and probably the final and long term one from the 7075.

Great report that you obviously spent a great deal of time on. I've shot a friends P22 and it was reliable. I just looked at a Ruger SR22 and the build quality IMO is higher. Unfortunately both pistols feel a little to small for me so I bought a Walther built Smith & Wesson M&P22 which Walther really did an excellent job fabricating. It's interesting having a S&W built by Walther.